Population = 135 students
Mean score = 72.3
Standard deviation of the scores = 6.5
Part (a): Students from 2SD and 3SD above the mean
2SD below and above the mean includes 95% of the population while 3SD includes 99.7% of the population.
95% of population = 0.95*135 ≈ 129 students
99.7% of population = 0.997*135 ≈ 135 students
Therefore, number of students from 2SD to 3SD above and below the bean = 135 - 129 = 6 students.
In this regard, Students between 2SD and 3SD above the mean = 6/2 = 3 students
Part (b): Students who scored between 65.8 and 72.3
The first step is to calculate Z values
That is,
Z = (mean-X)/SD
Z at 65.8 = (72.3-65.8)/6.5 = 1
Z at 72.3 = (72.3-72.3)/6.5 = 0
Second step is to find the percentages at the Z values from Z table.
That is,
Percentage of population at Z(65.8) = 0.8413 = 84.13%
Percentage of population at (Z(72.3) = 0.5 = 50%
Third step is to calculate number of students at each percentage.
That is,
At 84.13%, number of students = 0.8413*135 ≈ 114
At 50%, number of students = 0.5*135 ≈ 68
Therefore, students who scored between 65.8 and 72.3 = 114-68 = 46 students
Answer:
4.5 miles
Step-by-step explanation:
2 times as far as last week
last week was 2.25 miles
2* 2.25 = 4.5 miles
A decimal point. Im guessing you meant to say tenths instead of tens
Answer:
4/5
Step-by-step explanation:
Slope
Slope y-intercept of a line: y = mx + b
Where m is the slope and b is the y-intercept.
Answer:
Step-by-step explanation:
#8
step #1: <em><u>add $24.94 with $3.82</u></em>
24.94 + 3.82 = 28.76
Step #2: <u><em>subtract </em></u>
$50 - 28.76 = <u>$21.24</u>
